Field of the Invention
The present invention relates to an endoscope and particularly to a structure of a distal end portion of an endoscope provided with an elevator (forceps elevator) for a treatment tool and an elevating mechanism (elevator erecting mechanism) for the elevator.
Description of the Related Art
Regarding the endoscope, various treatment tools are inserted into a treatment-tool entry port provided on an operation portion and they are led out of the treatment-tool exit port opened in the distal end portion and used for treatment. The treatment tools such as a guide wire, a contrast medium tube and the like are used for a duodenoscopy, puncture needles for an ultrasonic endoscope, and forceps, snares and the like for a direct-viewing endoscope or a side-viewing endoscope, for example. These treatment tools need to change a derivation direction at the distal end portion in order to treat a desired position in a subject, and thus, a treatment-tool elevating mechanism (forceps elevator, hereinafter referred to as an “elevator”) is provided on the distal end portion.
As such the treatment-tool elevating mechanisms, a mechanism in which a wire is attached to the elevator and extended to a proximal end side of the endoscope, is known. In the mechanism, the elevator is rotated around a rotating shaft by pushing and pulling operation of the wire with an operation lever provided on the operation portion so as to change a position of the elevator between an erecting position and a reclining position. Moreover, a mechanism (lever type) in which the rotating shaft of the elevator is coupled with a housed lever through a partition wall, and the wire is attached to the lever is also known. In the mechanism, the elevator is rotated around the rotating shaft by means of the pushing and pulling operation of the wire with the operation lever provided on the operation portion so as to change the position of the elevator between the erecting position and the reclining position.
The distal end portion provided with such a treatment-tool elevating mechanism has a complicated shape and structure and thus, improvement of washing performances such as wraparound of a disinfectant, insertion of a washing brush (reachability of a tip end of the brush) or drainage and ease of a washing work are in demand. Conventionally an endoscope having a cap on the distal end portion and a detachable elevator is known (see Japanese Patent Application Laid-Open No. 6-315458, for example). In this type of endoscope, the cap and the elevator are removed after treatment, and the distal end portion is cleaned.